Problem with pyqt4

[eltico]

I need help from you guys..

I create this from pyqt4 designer
6297

but I need when click the buttons to open a dialog box asking for this for ex I have this:

lista=[]

def AgregarCoordenadas(coordenadas):
global lista
if isinstance (coordenadas,list)==True:
if ValidarEstructura (coordenadas)==True:
lista=coordenadas
else:
return ValidarEstructura(coordenadas)
else:
return formato()

I want the first button when click just to open a dialog box asking for "coordanadas" and OK an then its done lista=coordenadas..

how do I do that... im a newbie at gui

thanks